Lubricant containing ashless antiwear additives



nited rates Patent ii 3,088,91 l Patented May 7, 1963 This inventionrelates to improved lubricating oil compositions containing additivesthat function as wear-reducing agents. The antiwear additives of theinvention are particularly characterized by the fact that they aremetalfree, thus permitting them to be used where either ashlesscompositions or compositions relatively low in ashforming tendencies aredesired. The additives of this invention also have the desirableproperty of not contributing materially to oxidation or corrosioninstability.

In the formulation of crankcase lubricants for pistontype internalcombustion engines for automotive use, the recent trendhas been toemploy viscosity index improvers, oxidation inhibitors, and detergentsin order that the lubricant may serve its purpose under a wide varietyof conditions, including high-speed driving for sustained periods aswell as low-speed stop-and-go driving at relatively low temperatures.The detergents and oxidation inhibitor additives enable the oil to keepthe various parts of the engine free of varnish and cokelike deposits.At the same time, these additives prevent or at least minimize theformation of sludge and also hold in suspension any sludge that may beformed. There is one major disadvantage to detergents and inhibitors incrankcase lubricants, however, and that is that they keep the wearingsurfaces of the engine particularly clean. For this reason, theycontribute to a higher degree of wear than would occur if there were nodetergents and inhibitors present. This problem of wear with highdetergency oils shows up particularly in the valve train of automotiveengines and especially in the valve lifter mechanism. In the valvelifter mechanism, pressures as high as 100,000 lbs. per square inch canexist between the valve lifter and its actuating cam. For this reason,in present-day high detergency crankcase lubricants, there is a need forantiwear additives.

While in the past certain metal salts such as molyb denum sulfide andthe zinc salts of alkyl dithiophosphoric acids have been used asadditives for reducing wear, such metal salts have a disadvantage inthat they increase the over-all metal content of the lubricating oil.The oil composition may already be unduly high in metal content becauseof the presence of such detergent-inhibitors as overbased metalsulfonates, metal salts of alkyl phenol sulfides, metal carbonatedispersions, and the like. It is sometimes considered undesirable tohave large quantities of metal present in a crankcase lubricant becausethe metal may contribute to combustion chamber deposits which promotepreignition. It is self-evident that an antiwear agent which does notadd to the metal content of the lubricant will have a considerableadvantage. Also, there are obvious advantages for an ashless antiwearadditive in a formulation where the detergentinhibitor is of the ashlessvariety.

It has now been found that the mono salts (i.e. the half salts)formulated by the partial neutralization of chlorendic acid with longchain aliphatic amines of from about 12 to 24 carbon atoms are useful asashless antiwear additives for lubricating oils. Particularly useful arethe mono salt prepared from a C C aliphatic amine mixture of about 300molecular weight marketed commercially as Primene IMT by Rohm and Haas'Co., and the mono salt prepared from mixed hexadecyl andoctadecylamines of about 260 molecular weight marketed by Armour and Co.as Armeen HT. Other commercially available amines of this type includeDuorneen T (sometimes identified as N-tallow-1,3-diaminopropane), ArmeenCD (technical dodecylamine) and Primene 81R, which is a mixture of C toC aliphatic amines.

Chlorendic acid may be referred to as a dicarboxylic acid derivative ofa polychlorinated cyclopentadiene. This acid may also be identified asl,4,5,6,7,7-hexachlorobicyclo(22l)-5-heptene-2,3-dicarboxylic acid andhas the formula 0 II Gl-C-Cl 6 O l OOH /I II C H O 51 Chlorendic acidmay be prepared by the Diels-Alder addition of maleic anhydride tohexachlorocyclopentadiene and subsequent hydrolysis.

The invention will be more readily understood when reference is made tothe following examples.

EXAMPLE 1 EXAMPLE 2 The double salt of 'Primene JMT and chlorendic acidwas prepared in the manner of Example 1, using a ratio of 2 moles ofamine to 1 mole of acid.

EXAMPLE 3 The Armeen HT mono salt of chlorendic acid was prepared bydissolving 10.36 grams of Armeen HT (0.04 mole) in ml. of toluene andthen adding this solution to 15.54 grams (0.04 mole) of chlorendic acid.Toluene was then removed by heating the solution on a steam bath andblowing the product with air. The mono salt was recovered as a highlyviscous residue.

EXAMIPLE 4 The Primene JMT salt of monochlorodifiuoroacetic acid wasprepared by adding 43.5 grams (0.33 mole) of monochlorodifiuoroacticacid to grams (0.33 mole) of Primene J MT with stirring. The reactionwas exothermic but no external cooling was employed. The product was ared-brown thick oil.

EXAMPLE 5 In the same manner as in Example 4, the Primene JMT salts oftrichloroacetic acid, monochloroacetic acid, and heptafluorobutyric acidwere prepared by reaction of equimolar proportions of the amine with therespective acids.

EXAMPLE 6 Using as the base stock a refined mineral white oil having aviscosity of 78 centistokes at 100 F., a number of blends were preparedeach containing 1 wt. percent of phenyl alpha naphthyl amine as acorrosion and oxidation inhibitor and 0.5 wt. percent of one of thesalts described in Examples 1, 2, 4, and 5. Each of the compositions wassubjected to an oxidation and corrosion stability test at 347 F.,conducted in accordance with Method 5308.4 of Federal Test MethodStandard No. 791 as outlined in Military Specification MIL-L-7808D. Thecorrosion and oxidation results obtained with each of the compositionsare presented in Table I. It will be noted that the chlorendic acid monosalt of the present invention exhibited low corrosion tendencies towardthe various metals. Furthermore, the mono salt of the present inventionshowed much less oxidation promoting tendency than any of the othersalts as demonstrated by the markedly lower increase in viscosity andthe much lower total acid number of the oil at the end of the test.

Table I RESULTS OF OXIDATION AND CORROSION STABILITY TESTS AT 347 F. ONVARIOUS PRIMENE JMT SALTS OF HALOGENATED ACIDS Chlorendie ChlorendicTrichloro- Chloro- Chloro- Hcptw- Corrosion Results None Acid Acidacetic acetic difluorfluoro- Double Mono Acid Acid acetic butyrlc SaltSalt Acid Acid Metal Wt. Change mgJcmfi: Cu +0. 01 5. 1 0. 42 0. 20 0.77 -1.02 -0. 29 Mg- +0. 04 +0. +0.02 +0. 16 +0. 02 +7. 6 Fe 0 0 +0.01+0. 01 +0. 04 0. 01 0. 01 AL... V 0 +0. 02 +0. 02 +0.02 +0. 04 0 '0. 03Ag +0. 03 +0. 00 +0. 04 -0. 04 +0.07 +0. +0. 04 Oxidation Results: v r

ViS. at 100 F., 05---..- 83. 2 100. 15 92. 6 124. 8 123. 9 127. 4 148. 0Total Acid Number" 0.64 3. 85 0. 65 4.11 5.01 5.78 3. 48

EXAMPLE 7 as for example the complex ester formed by the reactionCompositions were prepared using as the base oil a high viscosity indexmineral oil composition containing a mixture of copolymeric typeviscosity index improvers and meeting the viscosity specifications of anSAE 10W-30 motor oil. The base oil also contained 0.2 wt. percent of apour point depressant and 0.06 wt. percent of a polyethylene glycoldioleate rust inhibitor. All of the compositions contained equal amountsof a detergent-inhibitor comprising a stabilized colloidal bariumcarbonate-phenate complex. One composition contained 1 wt. percent ofsulfurized sperm oil; the second composition contained 1 wt. percent ofthe mono salt of Primene JMT and the chlorendic acid prepared as inExample l; and the third contained the mono salt of Armeen HT andchlorendic acid prepared as in Example 3.

Each of these compositions was tested in the wellknown Shell four-ballwear testing machine. The test is conducted as follows. The testlubricant is placed in the cup of the machine and heated to 200 F. Thetest cup contains three steel balls which are fixed in position by ascrew cap. A fourth steel ball, which is held in a chuck, is pressedagainst the three lower balls with a force of 40 kilograms and isrotated at a speed of 600 rpm. for a period of 2 hours. At the end ofthe test, the amount of Wear is determined by measuring the diameter ofthe wear scar on each of the three lower balls and averaging theresults.

The compositions of the three blends tested and the wear resultsobtained are given in Table II. It will be seen that there was much lesswear with the compositions containing the salts of the present inventionas compared with the composition containing sulfurized sperm oil, whichhas been used in the past for reducing wear.

Table II FOUR-BALL WEAR TESTS 1 51. 8 wt. percent concentrate in mineraloil, 10. 61 BaO content.

of 1 mole of sebacic acid with 2 moles oftetraethylene glycol and 2moles of Z-ethyl hexanoic acid.

The additives of this invention are particularly appli cable for use inlubricating oil compositions containing viscosity index improvers, e.g.,polymethacrylates, poly butenes, etc., and detergent-inhibitors, e.g.metal sulfo nates, metal alky'l phenol sulfides, metal carbonate sols,phosphosulfurized hydrocarbon derivatives, and the like. The lubricantcompositions may also contain antioxidants, e.g.phenyl-alpha-naphthylamine, his phenols, etc., pour point depressants,dyes, and other additives for improving the properties of thecompositions.

The antiwear additives of the invention may also be employed inconjunction with any of the ashless types of detergents, for example,those of the high molecular weight polymeric type having molecularweights of up to about 50,000. One example is a copolymer of 65 toweight percent of mixed (l -C fumarates, 10 to 20 weight percent ofvinyl acetate, and 5 to 15 weight percetn of N-vinyl pyrroiidone.Another example is the copolymer derived by reaction of mixed tallowfurnarates and C oxo fumarates, averaging about 420 molecular weight,with vinyl acetate in a 3 to 1 acetate fumarate ratio, and 3 weightpercent of maleic anhydride, followed by subsequent removal of excessvinyl acetate. By tallow fium-arates is meant the esters of fumaric acidand the alcohols derived by hydrogenation of tallow. The latter areprincipally C and C alcohols with minor amounts of C C and C alcohols. Coxo alcohols are prepared rby reaction of carbon monoxide and hydrogenon mixed C C olefins followed by hydrogenation of the resultingaldehyde/s.

The compositions embodying the additives of this invention include notonly automotive crankcase lubricants but also such other lubricants andfluids as turbine oils, various industrial oils, hydraulic fluids,transmission fluids, and the like. A particular application of theadditives is as a replacement for zinc salts of dialkyl dithiophosphoricacids as antiwear agents in fluids for automatic transmissions, wherethe zinc salts suiier the disadvantage of poor lheat stability at hightemperatures, e.-g. 300 F. or higher. The compositions of Example 7 canserve as automatic transmission fluids for example.

The antiwear additives of this invention may be employed in lubricatingcompositions in concentrations ranging from about 0.01 to about 5percent by weight, preferably about 0.1 to about 2 percent by weight.

It is to be understood that the examples presented herein are intendedto be merely illustrative of the invention and not as limiting it in anymanner; nor is the invention to be limited by any theory regarding itsoperability. The scope of the invention is to be determined by theappended claims.

What is claimed is:

1. An improved lubricating composition h-avin-g superior antiwearproperties which comprises a major proportion of an oil of lubricatingviscosity grade into which has been incorporated from about 0.01 toabout 5 weight percent of the mono salt of chlorendic acid and analiphatic amine having in the range of from 12 to 24 carbon atoms.

2. The lubricating composition as defined by claim 1 15 wherein saidlubricating oil is a mineral oil.

3. The lubricating composition as defined by claim 1 which includes adetergent additive.

5 wherein said amine comprises mixed hexadecyl and octadecyl amines.

References Cited in the file of this patent UNITED STATES PATENTS2,733,248 Lidov Jan. 31, 1956 2,771,423 Dorinson Nov. 20, 1956 2,971,913David et a1. Feb. 14, 1961 OTHER REFERENCES HET Acid, HookerElectrochemical Co., Niagara Falls, 1952, page 4.

1. AN IMPROVED LUBRICATING COMPOSITION HAVING SUPERIOR ANTIWEARPROPERTIES WHICH COMPRISES A MAJOR PROPORTION OF AN OIL OF LUBRICATINGVISCOSITY GRADE INTO WHICH HAS BEEN INCORPORATED FROM ABOUT 0.01 TOABOUT 5 WEIGHT PERCENT OF THE MONO SALT OF CHLORENDIC ACID AND ANALIPHATIC AMINE HAVING IN THE RANGE OF FROM 12 TO 24 CARBON ATOMS.